This invention relates to the field of copolymers, especially to copolymers having repeating units arranged in a regularly repeating sequence.
The subject matter of this invention is related to that of an application filed on the same date entitled "Condensation Copolymers With Sequenced Monomer Structure", and designated Docket Number 1464.
In common polymerization methods, monomers are combined in the reaction vessel and allowed to react at random. Unless there is only one way that the polymer can form, sequences of repeating monomeric units in the copolymer will be random.
Random sequences are expected whenever a polymer is formed from two different monomers that have the same functional groups. An example of such a random copolymer is a copolyester made from two monomers which each have a hydroxy and a carboxyl functionality, or a copolyamide in which each monomer has an amine and a carboxyl functionality. Another example is where more than two different monomers are combined, e.g. when two diols and one diacid form a polyester.
Ordered sequences are ordinarily expected only in polymers made from a single monomer, or from two monomers that have different functionalities, e.g., when a diol and a diacid form a polyester.
Controlled sequences are known to occur in biological processes where specific complex molecules act as templates or sequence controllers, e.g., DNA or RNA control in the growth of proteins. However, molecules are not available which similarly control the sequence of synthetic copolymers of the type described herein.
In block copolymers, different polymer sequences are formed as prepolymers and these prepolymers are then bonded together to form a polymer in which different regions in the polymeric chain exhibit different properties.